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Lower Devonian coalified sporangia from Shropshire: Salopella Edwards & Richardson and Tortilicaulis Edwards
Authors:D. EDWARDS  U. FANNING  J. B. RICHARDSON
Affiliation:Department of Geology, University of Wales College of Cardiff, P.O. Box 914, Cardiff CF1 3YE;Department of Palaeontology, Natural History Museum, London, SW7 5BD
Abstract:A diverse assemblage of coalified sporangia from Lochkovian/Gedinnian, fluvial rocks imicrornatus-newportensis Spore Biozone) contains fusiform forms assignable to Salopella Edwards & Richardson and Tortilicaulis Edwards. Both show bifurcation within some sporangia. In specimens assigned to Salopella cf. marcensis , longitudinal dehiscence produces two equal valves revealing spores resembling Aneurospora , although trilete marks may be difficult to distinguish. The spores are in two forms with distal ornament of either coarse or fine coni, each occurring in separate sporangia. A further sporangium of Salopella shape contains distally apiculate, hilate cryptospores. Elongate sporangia exhibiting spiralling of superficial cells and sometimes gross twisting, are placed in a new species of Tortilicaulii, T. offaeus. Anatomical data include details of irregularly thickened epidermal cells, sporangial wall and in situ spores. The latter are trilete, equatorially thickened and highly distinctive, because the entire exospore surface is covered with grana, a feature not common in dispersed spores of this age. The nomenclatural and curatorial problems associated with these small, coalified fossils, whose anatomical examination by scanning electron microscope necessitates elimination of gross morphology, are discussed.
Keywords:ryptospores dehiscence dyads    in situ spores    rhyniophytoid
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